The development system is: MacBook Pro Intel i9 MacOS Big Sur 11.4 gcc version 11.1.0 (Homebrew GCC 11.1.0_1) clang version 12.0.0 I'm having trouble compiling some examples from the book 'Boost C ++ Application Development Cookbook’. The problem occurs only with g ++, with clang there is no error. Mistakes only occur when linking to -lboost_program_options, -lboost_system and -lboost_filesystem, with any other library (eg -lboost_chrono) everything is fine. Furthermore, it should be noted that by linking with -lboost_system and -lboost_filesystem no compilation / linking errors are obtained but we get a SEGMENTATION FAULT (ONLY when compiling with g++, compiling with Clang the program run fine), instead linking with -lboost_program_options results in linking errors. This is the example: #include #include <iostream> namespace opt = boost::program_options; int main(int argc, char *argv[]) { // Constructing an options describing variable and giving it a // textual description "All options" opt::options_description desc("All options"); // When we are adding options, first parameter is a name // to be used in command line. Second parameter is a type // of that option, wrapped in value<> class. Third parameter // must be a short description of that option. desc.add_options() ("apples", opt::value<int>(), "how many apples do you have") ("oranges", opt::value<int>(), "how many oranges do you have") ("help", "produce help message") ; // Variable to store our command line arguments opt::variables_map vm; // Parsing and storing arguments opt::store(opt::parse_command_line(argc, argv, desc), vm); // Must be called after all the parsing and storing opt::notify(vm); if (vm.count("help")) { std::cout << desc << "\n"; return 1; } std::cout << "Fruits count: " << vm["apples"].as<int>() + vm["oranges"].as<int>() << std::endl; } and these are the errors: Undefined symbols for architecture x86_64: "__ZN5boost15program_options11to_internalERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZN5boost15program_options11to_internalINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEEESt6vectorIS7_SaIS7_EERKS8_IT_SaISB_EE in ccmlvHtI.o "__ZN5boost15program_options16validation_error12get_templateB5cxx11ENS1_6kind_tE", referenced from: __ZN5boost15program_options16validation_errorC1ENS1_6kind_tERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_i in ccmlvHtI.o "__ZN5boost15program_options19options_descriptionC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEEjj", referenced from: _main in ccmlvHtI.o "__ZN5boost15program_options20invalid_option_valueC1ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZN5boost15program_options8validateIicEEvRNS_3anyERKSt6vectorINSt7__cxx1112basic_stringIT0_St11char_traitsIS7_ESaIS7_EEESaISB_EEPT_l in ccmlvHtI.o "__ZN5boost15program_options22error_with_option_nameC2ERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEES9_S9_i", referenced from: __ZN5boost15program_options16validation_errorC1ENS1_6kind_tERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_i in ccmlvHtI.o "__ZN5boost15program_options3argB5cxx11E", referenced from: __ZNK5boost15program_options11typed_valueIicE4nameB5cxx11Ev in ccmlvHtI.o "__ZN5boost15program_options6detail7cmdline21set_additional_parserENS_9function1ISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_ERKSA_EE", referenced from: __ZN5boost15program_options25basic_command_line_parserIcE12extra_parserENS_9function1ISt4pairINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESA_ERKSA_EE in ccmlvHtI.o "__ZN5boost15program_options6detail7cmdlineC2ERKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaIS9_EE", referenced from: __ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc in ccmlvHtI.o "__ZN5boost15program_optionslsERSoRKNS0_19options_descriptionE", referenced from: _main in ccmlvHtI.o "__ZNK5boost15program_options22abstract_variables_mapixERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZNK5boost15program_options13variables_mapixERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE in ccmlvHtI.o "__ZNK5boost15program_options22error_with_option_name23substitute_placeholdersERKNSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEE", referenced from: __ZTVN5boost15program_options20invalid_option_valueE in ccmlvHtI.o __ZTVN5boost15program_options16validation_errorE in ccmlvHtI.o __ZTVN5boost10wrapexceptINS_15program_options16validation_errorEEE in ccmlvHtI.o __ZTVN5boost10wrapexceptINS_15program_options20invalid_option_valueEEE in ccmlvHtI.o "__ZNK5boost15program_options29value_semantic_codecvt_helperIcE5parseERNS_3anyERKSt6vectorINSt7__cxx1112basic_stringIcSt11char_traitsIcESaIcEEESaISB_EEb", referenced from: __ZTVN5boost15program_options11typed_valueIicEE in ccmlvHtI.o ld: symbol(s) not found for architecture x86_64 collect2: error: ld returned 1 exit status The terminal process "zsh '-c', 'g++-11 -g -I/usr/local/Cellar/boost/1.76.0/include/ -I/usr/local/include/ -L/usr/local/Cellar/boost/1.76.0/lib/ -lboost_program_options -std=gnu++20 Chapter01/01_A_program_options_base/main.cpp -o Chapter01/01_A_program_options_base/main'" terminated with exit code: 1. The compile options are (Visual Studio Code): "label": "Build with g++ 11", "type": "shell", "command": "g++-11", "args": [ "-g", "-I/usr/local/Cellar/boost/1.76.0/include/", "-I/usr/local/include/", "-L/usr/local/Cellar/boost/1.76.0/lib/", "-lboost_program_options", // "-lboost_system", // "-lboost_filesystem", // "-lboost_chrono", "-std=gnu++20", "Chapter01/01_A_program_options_base/main.cpp", // "-L/usr/local/Cellar/gcc/11.1.0_1/lib/gcc/11/", "-o", "Chapter01/01_A_program_options_base/main" ] Thanks Stefano Gragnani